<!DOCTYPE html>
<html lang="zh-cn">
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Bootstrap</title>


    <link href="css/bootstrap.min.css" rel="stylesheet">


  </head>
  <body>
    <div class="container">
        <div class="row">
          <div class="col-sm-9">
            Level 1: .col-sm-9
            <div class="row">
              <div class="col-xs-8 col-sm-6">
                Level 2: .col-xs-8 .col-sm-6
              </div>
              <div class="col-xs-4 col-sm-6">
                Level 2: .col-xs-4 .col-sm-6
              </div>
            </div>
          </div>
        </div>
    </div>

    <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
    <script src="../js/jquery-1.12.3.js"></script>
    <!-- Include all compiled plugins (below), or include individual files as needed -->
    <script src="js/bootstrap.min.js"></script>
  </body>
</html>